package com.feng.nuike.huawei;

import java.util.*;

/**
 * @author feng
 * @decrition
 * @date 2022/2/170:09
 */
public class HJ10 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String s = scanner.nextLine();
        char[] chars = s.toCharArray();
        Set<Character> set = new HashSet<>();
        for (char aChar : chars) {
            if (aChar >= 0 && aChar <= 127) {
                set.add(aChar);
            }
        }
        System.out.println(set.size());
    }

}
